### CmdAdd Sidecar Workflow

`CmdAdd` is triggered when there is a new pod created. This runs on the node, in a chain of CNI plugins - Istio is
run after the main CNI sets up the pod IP and networking.

1. Check k8s pod namespace against exclusion list (plugin config)

* Validate that there is an `item_id` in the path for `GET` and `PUT` requests.
* Validate that the `item_id` is of type `int` for `GET` and `PUT` requests.
    * If it is not, the client will see a useful, clear error.
* Check if there is an optional query parameter named `q` (as in `http://127.0.0.1:8000/items/foo?q=somequery`) for `GET` requests.
    * As the `q` parameter is declared with `= None`, it is optional.